677c0d3e5d3ed46c664d44c1 241220 Prodmod Alphaomega Ai Pwm Controller

PWM Controller Tailored for AI Server and Graphics Cards Based on Blackwell GPUs

Jan. 6, 2025

The four-phase PWM controller pairing with Alpha and Omega’s benchmark DrMOS exhibits the best system efficiency for NVIDIA’s Blackwell GPU platforms.

Lee Goldberg

Related To: Electronic Design

According to Alpha and Omega Semiconductor (AOS), its AOZ73004CQI is the first four-phase controller for Blackwell GPUs. The controller’s advanced design has received full OpenVReg (open voltage regulator) OVR4-22 compliance.

The AOZ73004CQ controller’s Blackwell-optimized feature set includes a cycle-by-cycle current limit that meets the platform’s overcurrent-limit (OCL) specification, which helps safely throttle GPU power for maximized performance. It also includes an external reference input and PWMVID dynamic output voltage control, also compliant with the OVR4-22 specification.

The pulse-width-modulation (PWM) control outputs use a combination of intelligent algorithms and high sample rates to minimize ripple effects, enabling the device to triple the PWMVID slew rate up to 30 mV/µs (required for most next-generation GPUs). In addition, the AOZ73004CQI’s deep-off and shallow-off power states help it minimize power consumption, providing a significant advantage in battery-powered applications.

The AOZ73004CQI isn’t limited to being paired with four DrMOS as a standard application. Thanks to the precise turn-on time of AOS’s proprietary DrMOS technology, the AOZ73004CQI can enable a single PWM output to drive two or three DrMOS devices. This enables designers to create a cost-effective, high-power, multiphase power solution capable of supporting up to 12 power stages.

Similarly, the controller can pair with DrMOS power stages such as AOZ5316NQI/AOZ5317NQI/AOZ5318NQI, which are well-suited to laptop GPUs powered by a 20-V input.

Additional features include:

Differential remote sensing to achieve 1% regulated V_OUT accuracy.
Proprietary, high-performance AOS Advanced Transient Modulator (A²TM) control scheme.
Seamless CCM to DCM control to maximize efficiency.
Supports DCR or RON_LG sensing current balance.
Automatic phase shedding (APS) with user-settable threshold.
Acoustic noise suppression.

Housed in a QFN 4x4-32L package, the AOZ73004CQI is immediately available in production quantities with a lead time of 12 to 16 weeks. Pricing for AOZ73004CQI starts at $1.20 in 1,000-piece quantities.

About the Author

Lee Goldberg | Contributing Editor

Lee Goldberg is a self-identified “Recovering Engineer,” Maker/Hacker, Green-Tech Maven, Aviator, Gadfly, and Geek Dad. He spent the first 18 years of his career helping design microprocessors, embedded systems, renewable energy applications, and the occasional interplanetary spacecraft. After trading his ‘scope and soldering iron for a keyboard and a second career as a tech journalist, he’s spent the next two decades at several print and online engineering publications.

Lee’s current focus is power electronics, especially the technologies involved with energy efficiency, energy management, and renewable energy. This dovetails with his coverage of sustainable technologies and various environmental and social issues within the engineering community that he began in 1996. Lee also covers 3D printers, open-source hardware, and other Maker/Hacker technologies.

Lee holds a BSEE in Electrical Engineering from Thomas Edison College, and participated in a colloquium on technology, society, and the environment at Goddard College’s Institute for Social Ecology. His book, “Green Electronics/Green Bottom Line - A Commonsense Guide To Environmentally Responsible Engineering and Management,” was published by Newnes Press.

Lee, his wife Catherine, and his daughter Anwyn currently reside in the outskirts of Princeton N.J., where they masquerade as a typical suburban family.

Lee also writes the regular PowerBites series.